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Omaha symptom guide

What Do Holes, Cracks, Peeling Bark, or Ooze Mean?

Bark holes, tunnels, cracks, scars, peeling areas, or ooze can reflect insects, weather, mechanical injury, decay, or disease. Shape, location, pattern, host, and timing all matter.

Sources checked: 2026-07-26Next source review due: 2027-01-26Independent professional review: not completed

What this page is for

Organize the observation before choosing action

Help homeowners collect useful bark evidence without cutting, probing, climbing, or deciding removal from an image match.

This page does not identify the cause, recommend chemical treatment, or determine that pruning or removal is needed.

What to notice

  • Photograph the mark in context and close up with a safe scale reference; record whether it repeats around the trunk or appears near a wound.
  • Note recent storms, freeze, mower/string-trimmer injury, construction, and whether canopy decline appears above the area.

Plausible categories to compare

These are not ranked probabilities and do not form a diagnosis.

Insect activity

Some borers leave characteristic holes or galleries, but other insects and old damage can look similar.

Weather or mechanical injury

Freeze, sun exposure, storms, equipment, and rubbing can injure bark without establishing a disease.

Decay, canker, or other disease process

A diagnostic review may need host, distribution, live/dead tissue, and a sample to distinguish these causes.

What to document from the ground

  • whole tree
  • entire trunk and root flare
  • close-up with safe scale
  • canopy above the mark
  • date first noticed and recent damage history

Safety boundary

Do not probe cavities, peel bark, climb, or stand below damaged limbs. Pair a major crack, split, lean, root movement, or target below with the Hazard Assessment.

Use the Hazard Assessment

Related named references

These names are useful for further research, not confirmation of what is affecting a specific tree.

Emerald Ash Borer (EAB)Oak WiltFire BlightWinter or Freeze Damage

Sources